readme: add notes for macOS

README.md

@@ -1,5 +1,7 @@
-Spice agent for Linux
-=====================
+Spice agent for Linux and macOS
+===============================
+
+### Linux
 
 The spice agent for Linux consists of 2 parts, a daemon spice-vdagentd and
 a per X-session process spice-vdagent. The daemon gets started in Spice guests
@@ -27,7 +29,16 @@ Features:
 * Limited support for setups with multiple Screens (multiple qxl devices each
   mapped to their own screen)
 
-## Install
+### macOS
+
+Similar to Linux, the SPICE agent has a LaunchDaemon spice-vdagentd which
+handles communication with the console port and a LaunchAgent spice-vdagent
+that runs for each logged in user. Note that there is no protection against
+one logged in user from snooping another user's clipboard when this is running.
+
+The macOS agent currently only supports clipboard features.
+
+## Install (Linux)
 
 From inside your virtual machine (e.g., GNOME Boxes), use your guest system’s
 package manager to install.
@@ -38,6 +49,33 @@ For example, if you’re running a Debian/Ubuntu derivative in a VM, use:
 sudo apt install spice-vdagent
 ```
 
+## Build (macOS)
+
+Currently, you can only build on Apple Silicon Macs with Homebrew installed in
+both native and Rosetta. This is because we require GLib installed in both
+architectures at the default location.
+
+>>>
+    $ /opt/homebrew/bin/brew install glib # arm64
+    $ /usr/local/bin/brew install glib # x86_64
+>>>
+
+Then, you can build the project with Xcode or `xcodebuild`
+
+>>>
+    $ xcodebuild archive -scheme vd_agent -archivePath vd_agent.xcarchive
+>>>
+
+Afterwards, you can sign the output and create an installer package with a paid
+Apple Developer certificate (Developer ID Application and Developer ID
+Installer are both needed).
+
+>>>
+    $ ./package_macos.sh vd_agent.xcarchive spice-vdagent-x.yy.pkg
+>>>
+
+You may then wish to notarize it before distributing.
+
 ## How it works
 
 All vdagent communications on the guest side run over a single pipe which
@@ -53,6 +91,11 @@ Under Linux this virtio serial port has the following name:
     /dev/virtio-ports/com.redhat.spice.0
 >>>
 
+Under macOS this virtio serial port has the following name:
+>>>
+    /dev/tty.com.redhat.spice.0
+>>>
+
 To enable the virtio serial port you need to pass the following params on
 the qemu cmdline: